Transcript Warm- up Quiz (worth 20 points) Define the terms

California Science Content
Standards Covered:
► Plate
tectonics operating over geologic
time has changed the patterns of land,
sea, and mountains on Earth's surface.
As the basis for understanding this
concept:
► 3D: Students know why and how
earthquakes occur and the scales used
to measure their intensities &
magnitude
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discuss the elastic rebound theory
Terms Chapter 6
Define and write sentences or draw pictures
1.
2.
3.
4.
5.
6.
7.
8.
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Earthquakes
Elastic rebound
theory
Aftershocks
Focus
Epicenter
Pacific ring of fire
Fault zones
Seismograph
9.
10.
11.
12.
13.
14.
15.
16.
17.
P waves
S waves
Surface waves
Magnitude
Microquakes
Mercalli scale
Intensity
Tsunami
Seismic gaps
discuss the elastic rebound theory
Chapter 6 Introduction
► Ring
of Fire
► Earthquakes 1 & 2
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Earthquakes
Chapter 6
3D: Students know why and how earthquakes occur and the scales used to measure
their intensities & magnitude
Elastic Rebound Theory
Anatomy of a Quake
Epicenter, focus, seismic waves
Fore, primary, aftershock
Shallow, intermediate & deep focus
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discuss the elastic rebound theory
Lecture 6.1
Discuss elastic rebound theory
►
Elastic Rebound Theory
 When a STRESS is applied, the road changes from its original
form – ELASTIC DEFORMATION
 When the RUPTURE relieves the STRESS, the ground under the
road REBOUNDS and returns to its original condition
 When the RUPTURE occurs, we feel the EARTHQUAKE
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discuss the elastic rebound theory
Lecture 6.1
Discuss elastic rebound theory
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discuss the elastic rebound theory
Explain why earthquakes generally occur
at plate boundaries
first occurs at the FOCUS
► The place on the SURFACE of the Earth
under the focus is the EPICENTER
► Slippage
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Explain why earthquakes generally occur
at plate boundaries
► 90%
of earthquakes have a SHALLOW
focus
► Intermediate
and deep
focus
earthquakes (10%) occur 70 Km and
DEEPER
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Explain why earthquakes generally occur
at plate boundaries
► How
does the depth of earthquakes explain
the type of a boundary?
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Explain why earthquakes generally occur
at plate boundaries
►3
Major Earthquake Zones
 Mid Ocean Ridges – mainly divergent
 Eurasian-Melanisian Belt – mainly convergent
 Ring of Fire – mainly convergent
►Each
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dot represents an EARTHQUAKE ZONE
discuss the elastic rebound theory
End Lecture 6.1
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Chapter 6 Section 2 Objectives
1.
2.
3.
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We will be able to compare the three types
of seismic waves.
We will discuss the method scientist use to
pinpoint an earthquake.
We will discuss the method most
commonly used to measure the magnitude
of earthquakes.
discuss the elastic rebound theory
Recording Earthquakes
Lecture 6.2
► Seismic
waves are
recorded on a
seismograph
►3
Major forms of waves
recorded by
seismograph
 P Waves
 S Waves
 Surface Waves
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P Waves
aka Primary Waves
► Travel the fastest
► Same direction as particle motion
► Travel FASTER through DENSER material
► Move through solids, gases and liquids
►
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S Waves
aka secondary or shear waves
► SLOWER than P Waves
► Travel at RIGHT Angles to particles in
motion
► CANNOT pass through liquid or gases
►
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How to find the epicenter
► Method:
TRIANGULATION
► Must
have three (3) seismographs
► Calculate the difference in P wave travel
from all three
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Triangulation – Where is the epicenter
located?
This map shows how the epicenter of the Loma Prieta earthquake was determined using
data from three seismic stations. The seismogram at Eureka, CA indicated that the epicenter
was 478 km away (red circle). The green circle represents the distance of the epicenter (624
km) from Las Vegas. The blue circle represents the distance of the epicenter (702 km) from
Elko, NV. The epicenter is determined by the intersection of all three circles near Santa
Cruz, CA. This triangulation technique requires data from at least three seismic
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the elastic rebound theory
stations in order to determine thediscuss
epicenter.
Earthquake Measurement
►
Magnitude is a measure of
ENERGY RELEASED IN AN
EARTHQUAKE
 Measured by a RICHTER SCALE
►
Intensity is the amount of
DAMAGE an earthquake
causes
 Measured by the MERCALLI
SCALE
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► Big
Lecture 6.2
Idea Question #2
 What is the difference between intensity and
magnitude? What scales are used to measure each?
► End
of Chapter Questions
 p. 112-113 #8-11
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TEST QUESTION:
Circle on the diagram the location of the
epicenter
The seismogram in Pusan, Korea indicated that the epicenter was 549 km away (red circle). The green circle represents the
distance of the epicenter (435 km) from Tokyo. The blue circle represents the distance of the epicenter (697 km) from Akita,
Japan. The epicenter is determined by the intersection of all three circles in Kobe. This triangulation technique requires data
from at least three seismic stations in order to determine the epicenter.
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Essential Questions Chapter 6
Section 3
► Describe
the possible effects of a major
earthquake on buildings
► Discuss the relationship of tsunamis to
earthquakes
► List safety rules follow when an earthquake
strikes
► Identify changes in the earth’s crust that may
signal earthquakes
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identify changes in the earth’s crust that may
signal earthquakes
Describe the possible effects of a
major earthquake on buildings
► Earthquake
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Damage ► Most injuries, result of
collapsing buildings or falling
objects.
► Types of damage –
landslides, fires, broken gas
and electric lines, flooding,
and damage to dams
► The longer an earthquake
last the more damage it
causes
identify changes in the earth’s crust that may
signal earthquakes
Describe the possible effects of a
major earthquake on buildings
► Destruction
to
buildings and property
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► Buildings
are not
designed to sway, walls
can collapse, may tip
over
► Type of ground, solid
ground offers more
support to buildings,
loose soil can cause
more swaying in
buildings
identify changes in the earth’s crust that may
signal earthquakes
Discuss the relationship of tsunamis to
earthquakes
► Tsunamis
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► Caused
by underwater
earthquakes, that either
cause a landslide or
faulting underwater.
► Faulting can change
seafloor elevation,
forcing the water to
move up and down.
► Underwater landslide
can cause this same up
and down motion.
identify changes in the earth’s crust that may
signal earthquakes
Discuss the relationship of tsunamis to
earthquakes
► There
► Tsunamis
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is an early
warning system to alert
areas of tsunamis.
identify changes in the earth’s crust that may
signal earthquakes
List safety rules follow when an
earthquake strikes
► Earthquake
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Safety
► Before
an earthquake
 Be prepared – have
canned food, bottled
water, flashlights,
batteries and a portable
radio.
 Plan what to do when a
earthquake happens
 Learn how to turn off gas,
water and electricity to
the house.
identify changes in the earth’s crust that may
signal earthquakes
List safety rules follow when an
earthquake strikes
► Earthquake
Safety
► During
an earthquake
 Stay calm and get to a
safe position
 Indoors – protect
yourself from falling
objects.
 Outside – stay away
from tall buildings,
power lines, bridges, or
tunnels
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identify changes in the earth’s crust that may
signal earthquakes
List safety rules follow when an
earthquake strikes
► Earthquake
Safety
► After
the earthquake
 Check for hazards,
always wear shoes,
and avoid power lines
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identify changes in the earth’s crust that may
signal earthquakes
Identify changes in the earth’s crust that may
signal earthquakes
►
Earthquake
warnings &
predictions
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Animals behavior & past earthquakes used
to predict future earthquakes, may be years
off
► Fault stress measured to determine seismic
gaps, to determine where a quake may
happen.
► Instruments used to detect crust tilting, rock
stress, water flow changes, electro magnetic
changes to predict earthquakes.
► Decreases in P-wave speed may tell when a
quake is coming.
► Most methods are not very reliable in
predicting an earthquake
►
identify changes in the earth’s crust that may
signal earthquakes